Mental health disorders affect millions of U.S. adults each year. Some disorders are mild, and others are more disabling and require intensive management and care.

The majority of people suffering from mental disorders can effectively return to normal, productive lives if they receive appropriate treatment -- treatment that is readily available.

According to the National Institute of Mental Health, mental health disorders account for four of the top 10 causes of disability in the U.S. and include major depression (also called clinical depression), manic depression (also called bipolar disorder), schizophrenia, and obsessive-compulsive disorder.

An estimated 26 percent of people ages 18 and older, about one in four (or more than 57.7 million) U.S. adults, suffer from a diagnosable mental disorder in a given year.

About 18.8 million U.S. adults, or 9.5 percent, will suffer from a depressive illness (major depression, bipolar disorder, or dysthymia) each year. Many of them will be unnecessarily incapacitated for weeks or months because their illness is left untreated.